Bravecto vs. NexGard: Comparing 12-Week vs. Monthly Flea and Tick Protection

Bravecto and NexGard are both isoxazoline-class oral chews for dogs, but the dosing interval is their most practically significant difference: Bravecto provides 12 weeks of flea and tick protection per dose, while NexGard is dosed monthly. For dog owners who find monthly dosing difficult to maintain consistently, the 12-week interval is a meaningful advantage. For owners whose dogs tolerate monthly routines well, the coverage profiles may matter more than the dosing schedule.

These medications require a prescription from a licensed veterinarian. Consult your veterinarian before starting, changing, or stopping any prescription treatment for your pet.

FDA Black Box Warning: The FDA requires a black box warning on all isoxazoline-class products for rare but serious neurological adverse events including seizures, tremors, and loss of coordination. Dogs with a history of seizures or neurological conditions require veterinarian evaluation before use.

The Short Answer

Bravecto’s 12-week dosing interval means your dog gets the same annual number of protected days with four doses instead of twelve. NexGard’s monthly dosing gives you more frequent check-in points with your dog’s parasite protection — some owners prefer this for awareness purposes, and it aligns more naturally with monthly heartworm prevention routines. Neither approach is inherently safer or more effective than the other; the right choice involves your dog’s individual health history, tick species exposure, and your veterinarian’s recommendation.

Active Ingredients

Bravecto

Bravecto’s active ingredient is fluralaner, an isoxazoline compound that kills fleas and ticks. The 12-week duration is a pharmacokinetic property of fluralaner — it distributes into the subcutaneous fat tissue and is released over a longer period than afoxolaner (NexGard’s active ingredient).

NexGard

NexGard’s active ingredient is afoxolaner. It achieves peak plasma concentration within hours of dosing and provides effective coverage for 30 days, after which a new dose is needed to maintain protection.

Tick Species Coverage

Both products cover the major tick species of concern in North America:

• Black-legged tick (deer tick, vector for Lyme disease)
• American dog tick
• Brown dog tick
• Lone star tick

Coverage varies in terms of kill speed and which life stages are targeted. Your veterinarian can advise on which tick species are most prevalent in your area and whether there are reasons to prefer one product over the other based on regional tick exposure.

Dosing Interval Considerations

The 12-Week Advantage

For owners who travel frequently, have irregular schedules, or find monthly reminders difficult to maintain, Bravecto’s 12-week interval reduces the frequency of missed doses. A missed monthly dose means your dog goes unprotected for some portion of the month. A missed Bravecto dose matters more if it extends the gap beyond 12 weeks — but there is less opportunity to miss a dose when you are only dosing four times per year.

The Monthly Advantage

Monthly dosing aligns with most heartworm prevention products, which are also monthly. If your dog takes a separate monthly heartworm preventative, administering NexGard on the same schedule simplifies the routine. Monthly dosing also means that if you or your veterinarian want to change products, the transition happens at most 30 days out rather than up to 12 weeks out.

FDA Safety Warnings

Both Bravecto and NexGard are isoxazoline-class products and are subject to the same FDA-required black box warning for rare neurological adverse events including seizures, tremors, and loss of coordination. This warning applies to the entire isoxazoline class and is present on both product labels.

Dogs with a history of seizures or neurological disorders should be evaluated by a veterinarian before starting either product. Your veterinarian will weigh the clinical benefit of parasite prevention against the risk in the context of your specific dog’s history.

Report any adverse reactions to your veterinarian immediately and to the FDA at 1-888-FDA-VETS (1-888-332-8387).

Bottom Line

Bravecto and NexGard provide comparable flea and tick protection from the same drug class with different dosing intervals. The 12-week vs. monthly decision is primarily a practical one for most dogs — which schedule you are most likely to maintain consistently. Both decisions should be made in conversation with your veterinarian, who can evaluate your dog’s health history and local parasite risk to recommend the more appropriate option.

Find expert-reviewed pet care guidance at GetPetPros — with product comparisons, safety information, and veterinary resources.

Frequently Asked Questions

Is Bravecto or NexGard available without a prescription?

Both Bravecto and NexGard are prescription-only products in the United States. They require a valid veterinarian-client-patient relationship and a prescription before they can be dispensed. Products sold online or at non-veterinary retail locations as “equivalent” to prescription isoxazoline products should be evaluated carefully — prescription isoxazoline products are not legally sold without a prescription, and products claiming to replicate their effects without a prescription are not the same medication.

Can Bravecto be split or given at a half dose to make it last longer?

No. Bravecto should be given as a complete single dose as directed on the label and by your veterinarian. Splitting the dose or attempting to extend the dosing interval beyond 12 weeks reduces the concentration of the active ingredient in your dog’s system and may leave your dog unprotected. If cost is a concern, discuss this with your veterinarian — there may be options including payment plans, loyalty programs, or veterinary discount programs that make the full dose more accessible.

What should you do if your dog vomits within an hour of taking either chew?

Contact your veterinarian. Vomiting within a short period after dosing may mean the product was not fully absorbed. Your veterinarian will advise on whether re-dosing is appropriate and whether there are any safety concerns based on the amount of time that passed. Do not re-dose without veterinary guidance.

Does Bravecto’s 12-week duration mean it is stronger than NexGard?

Bravecto’s 12-week dosing interval reflects the pharmacokinetic properties of fluralaner — how the compound is absorbed, distributed, and eliminated in the dog’s body — not a higher potency compared to NexGard’s afoxolaner. Both compounds work by the same mechanism: blocking GABA-gated chloride channels in invertebrate nervous systems. The difference in dosing interval is a function of each compound’s half-life in the dog’s fat and tissue, not a measure of efficacy per dose. For owners, the practical implication is that Bravecto requires fewer annual doses (four versus twelve), which some find more convenient; but the per-month cost, overall compliance expectations, and the same black box warning requirements apply to both.

What is the age and weight minimum for each product?

NexGard (afoxolaner) is labeled for dogs and puppies 8 weeks of age and older, weighing at least 4 pounds. Bravecto (fluralaner) chews are labeled for dogs 6 months of age and older, weighing at least 4.4 pounds. This age difference is meaningful for owners of young puppies: a puppy ready for external parasite prevention at 8-10 weeks of age is eligible for NexGard but not yet eligible for Bravecto chews. Your veterinarian will recommend the appropriate product based on the puppy’s age, weight, and geographic parasite risk. There is also a Bravecto topical spot-on formulation with different age and weight parameters — your veterinarian can advise on label differences if relevant.

Can Bravecto and NexGard be used alongside heartworm prevention?

Yes — neither Bravecto nor NexGard provides heartworm prevention, so dogs in heartworm-endemic areas typically receive a separate monthly heartworm preventive alongside their flea and tick product. Common combinations include Bravecto or NexGard for external parasites alongside a heartworm-only oral product or a topical combination product. Your veterinarian will recommend based on your dog’s full parasite risk profile and geographic exposure. Simparica Trio and Interceptor Plus are examples of products that combine isoxazoline flea/tick coverage with heartworm prevention, which may reduce the total number of products a dog needs monthly.

What should an owner do if their dog vomits after taking a dose?

Both NexGard and Bravecto are given with or without food, though giving with food can reduce the likelihood of gastrointestinal upset. If a dog vomits within a short time of dosing — particularly within the first hour — contact your veterinarian, who can advise whether a replacement dose is needed. Vomiting that occurs several hours after dosing is less likely to have removed a meaningful amount of the product but is still worth mentioning at the next veterinary visit. Consistent GI upset with one product is a reason to discuss switching to an alternative with your veterinarian. Never re-dose without veterinarian guidance, as giving two doses close together creates risk of excess exposure.

Is there a situation where a veterinarian might recommend one over the other?

Veterinarians consider dosing compliance, the dog’s health history, owner preference, and geographic parasite risk when recommending between Bravecto and NexGard. Owners who reliably give monthly treatments may find NexGard’s shorter window sufficient; owners who travel frequently or whose dogs spend time in kennel environments may prefer Bravecto’s longer dosing interval as a compliance buffer. Dogs with a seizure history require a more nuanced conversation before starting any isoxazoline product. Neither product is broadly preferred over the other in veterinary practice — the recommendation is individualized to the patient and owner situation.